Investigators at USDA and JHU have continued to share interest in the potential immunological activity of cockroach debris left in dwellings after treatment with various insecticides and cleaning agents. The freeze-dried extracts of Cockroach debris and a pool of rabbit antiserum, prepared by LST with source material provided by ARS, are now the references of an ELISA system. This year, a repeated sampling of the homes of adolescent asthmatics in Baltimore, identified by Allergy/Asthma researchers at Johns Hopkins, were sampled and detectable cockroach materials were compared to previous results. Investigation related to assay reproducibility and variability has been initiated with the help of a statistican from JHU. JHU received an in-house grant that has been supplemented by a 3 year NIH grant awarded in July 1999. These grants will provide CBER with all necessary reagents, and supplies for testing as samples are collected.